Method for making hardened gelatin images

ABSTRACT

HARDENED GELATIN IMAGES ARE FORMED FROM SILVER HALIDE IMAGES IN THE PRESENCE OF (A) A SILVER HALIDE SOLVENT, (B) AN ALKALI AND (C) A COMPOUND REPRESENTED BY THE GENERAL FORMULA 1:   (+)N&lt;(-A-Y-C(=)-S-B-) X(-) WHERE N AND C ARE JOINED   WHEREIN A AND B ARE EACH NON-METAL ATOMS NECESSARY FOR FORMING A HETEROCYCLIC RING, Y IS A MEMBER SELECTED FROM THE GROUP CONSISTING OF SULFUR AND SELENIUM, AND X IS AN ANION.

United States Patent 3,745,013 METHOD FOR MAKING HARDENED GELATIN IMAGES Reiichi Ohi, Jun Hayashi, and Tadao Shishido, Minamiashigara, Kanagawa, Japan, assignors to Fuji Photo Film (30., Ltd., Minami-ashigara, Kanagawa, Japan No Drawing. Filed Oct. 18, 1971, Ser. No. 190,258 Claims priority, application Japan, Oct. 19, 1970, 45/913304 Int. Cl. G03c 1/30 U.S. Ci. 96-111 17 Uaims ABSTRACT OF THE DISCLOSURE Hardened gelatin images are formed from silver halide images in the presence of (a) a silver halide solvent, (b) an alkali and (c) a compound represented by the General Formula I:

wherein A and B are each non-metal atoms necessary for forming a heterocyclic ring, Y is a member selected from the group consisting of sulfur and selenium, and X is an anion.

BACKGROUND OF THE INVENTION (1) Field of the invention (2) Description of the prior art It has been Well known in the art that gelatin treated with a dichromate compound may be hardened by the action of light. It is also known that, when developed silver images are treated with an aqueous dichromate solution, the gelatin surrounding the silver grains may be hardened. Moreover, it is also known that such reaction can be applied to the formation of hardened images of gelatin and that by utilizing the diiference in aflinity to Water-soluble dyes or oily inks between the hardened and unhardened areas, corresponding imagewise duplicates can be produced. In addition, it has been frequently proposed to remove the gelatin from the unhardened areas to make the relief images which are to be utilized for the production of the corresponding duplicate. As another method for making the gelatin relief, there are known the so-called, tanning development and etching method. The gelatin relief prepared by these methods is very useful as a matrix for dye transfer processes or as a printing plate.

However, the above described methods using dichromates have a disadvantage in that the dichromates are interior to silver halides in light-sensitivity, While the tanning development or the like methods are also defective, in that they require special processing solutions, which present ditficulties in view of handling and storage.

images, which differs completely from the prior art methods.

3345,13 Patented July 10, 1973 Another object of this invention is to provide a novel and useful method for making gelatin relief images.

The above described objects have been accomplished by imagewise hardening gelatin under alkaline conditions in the presence of silver ions and at least one cyclic compound containing the following linkage:

Thus, according to the present invention, there is provided a method for making gelatin images which comprises hardening gelatin in the non-silver image areas of a silver image-carrying gelatin-silver halide emulsion layer in the presence of (a) a silver halide solvent, (b) an alkali agent and (c) at least one compound of the Formula I:

wherein A and B are each non-metal atoms necessary for forming a heterocyclic ring, Y is sulfur or selenium and X is an anion.

Furthermore, according to the present invention, there is provided a method for making hardened gelatin images, which comprises contacting a gelatin with a silver halide emulsion layer carrying a silver image in the presence of (a) a silver halide solvent, (b) an alkali agent and (c) at least one compound of the above-described General Formula I, whereby hardening gelatin in the areas of the gelatin layer corresponds to the nonsilver image areas of the emulsion layer.

The principle of the method for making hardened gelatin images according to the present invention will be explained as follows without limiting the scope thereof.

DETAILED DESCRIPTION OF THE INVENTION When a light sensitive material comprising a support bearing thereon a gelatin-silver halide emulsion layer is imagewise exposed and developed, the silver halide in the exposed areas will be reduced to form the metal silver images with the silver halide remaining intact in the unexposed areas, whereafter the light sensitive material is processed with an alkaline fixing solution in the presence of at least one compound of the above-described General Formula I, whereby the silver halide in the unexposed areas will be made soluble by the silver halide solvent contained in the fixing solution to thereby release silver ions. At this point, the silver ion concentration in the unexposed areas is suddenly increased, so that it seems that the selective formation of the hardened images of gelatin result from the gelatin-hardened action of the compound of the Formula I activated by the silver ions and the alkaline atmosphere. In short, the essential part of this invention is the simultaneous presence of (1) a gelatin layer for the hardened images to be formed thereon, (2) imagewise silver halide, (3) silver halide solvent, (4) alkali agent and (5) at least one compound of the General Formula I.

In the practice of making the hardened gelatin images according to the method of this invention, various embodiments can be contemplated, depending upon the manner in which the above-described five factors are provided. First, there may be mentioned the case where both gelatin and silver halide are present in the same layer. In such cases, the method of this invention may be applied, for example, in the manner wherein a light sensitive material comprising a support having thereon a gelatin-silver halide emulsion layer is processed, after exposure and development, with an alkaline fixing solution containing the compound(s) of Formula I. Alternatively, in such cases, the compound(s) of Formula I may be incorporated in the light sensitive material prior to fixing. That is, the compound(s) may be either previously incorporated into the emulsion layer upon manufacturing the light sensitive material, or treated, prior to fixing, with an aqueous solution of the compound(s) of Formula I for introduction into the emulsion layer. Next, there may be mentioned the case where gelatin and silver halide are each present in separate layers, for example, the case where a light sensitive material comprising a support coated successively thereon with a gelatin layer and then silver halide emulsion layer is employed. Also in such cases, the compound(s) of Formula I may be incorporated into the gelatin layer, silver halide emulsion layer and/or processing solution. Alternatively the processing may be carried out by superposing the developed light sensitive material on a gelatin layer of a sheet material, also in which cases, the compound(s) of For mula I may be incorporated into the gelatin layer, emulsion layer and/or processing solution, as in the above-described cases. The embodiments of any other type may be suitably adopted for the practice of the present invention.

The gelatin which is employed in this invention may be any of those conventionally employed in the field of photographic arts. It may advantageously constitute a layer by being coated on a suitable support. Into the gelatin layer may be incorporated the compound(s) of Formula I and optionally added various kinds of additives known in the art.

The silver halide emulsion may be any of these conventionally employed in photography, which comprises silver chlorine, silver bromide, silver iodide, silver chlorobromide, silver chlorobromoiodide or a mixture thereof dispersed in a high molecular weight substance, such as gelatin. It may optionally contain conventional chemical sensitizers, sensitizing dyes, stabilizers, hardeners and/or coating aids. That the present invention employs a lightsensitive substance comprising silver halide is particularly advantageous in view of sensitivity (speed) and light sensitive range. The light-sensitive silver halide emulsion may be applied onto a conventional support to form the light-sensitive layer.

Fixing compositions conventionally employed in the processing of the usual silver halide photographic materials contain thiosulfate such as sodium thiosulfate, ammonium thiosulfate, etc. The thiosulfate is one of the silver halide solvents and preferably employed in the present invention, although any other silver halide solvent may be employed as well. These silver halide solvents act as a precursor for silver ions.

The alkali agent is employed for the purpose of making the environment of the reaction alkaline, so that any of the alkali agents having such an efiect may be employed. Although the gelatin hardening reaction somewhat proceeds even in an acidic environment, it is necessary to effect the reaction in an alkaline environment, in order to obtain the hardened gelatin images suitable for the purpose of this invention. Although there may be obtained hardened gelatin images at a pH of about 8, higher pH values are more advantageous from a view point of processing time.

Typical examples of the compounds of Formula I are illustrated below:

Compound 1---..;. S S M.P. 258 C.

Compound 2 M.P. 288 C.

S V S -N 1 Compound 3.. S S M-P. 260 0.

Compound 4- S ESIS M.P. 267 C.

H3C i Componnd 5.....-..: S S M. P. 2 mo s f w 75 C Compound 6 Se /S M. P. 288 C- til Br- Compound 7--.:-.: (ST SW M. P. 235 C. N"!- Br- Compound 8- 8Y8 M. P. 291 0.

Compound 9. B S

H C-O-NQ 1) A mixture of 16 g. of Z-mthylthiobenzothizole and 20 g. of ethylene bromide was heated at a temperature of C. for 4 hours. The crystals formed upon cooling were collected by filtration and then recrystallized from ethanol to obtain 17 g. of crystals appearing as needles having a melting point of 258 C.

Synthesis 2 (Compound 3) A mixture of 16 g. of Z-methylthiobenzothiazole and g. of 1,3-dibrornopropane was heated at a temperature of 160 C. for 4 hours. After cooling, the precipitated crystals were filtered 011 and then recrystallized from ethanol to obtain 14 g. of crystals appearing as needles having a melting point of 260 C.

Synthesis 3 (Compound 6) A mixture of 20 g. of 2-methylthiobenzoselenazole and 20 g. of ethylene bromide was heated at a temperature of 160 C. for 4 hours. After cooling, the precipitated crystals were collected by filtration to obtain 18 g. of crystals appearing as needles having a manner as described in Chemical Abstracts, vol. 72, page 31666 (1970).

In accordance with this invention, by subjecting a conventional photographic light sensitive material having a gelatin-silver halide emulsion layer to exposure development and fixation, hardened gelatin images can be readily formed in the unexposed areas. The gelatin layer having the hardened gelatin images can be used, for example, in producing duplicates by means of impregnating the layer with a water-soluble dye followed by transferring the dye to a suitable material. Furthermore, gelatin relief images can be obtained by treating the gelatin layer with warm water, thereby removing the gelatin in the unhardened areas. Such gelatin relief images can be used in various fields, as those made in known manners. Some examples of their specific utilities are illustrated as follows, although other utilities will be apparent to those skilled in the art.

(1) They may be used as ofi-set printing plates. In such cases, the surface of a support is used as the oleophilic ink depositing site and a gelatin layer as the hydrophilic site. Since the conventional off-set printing plates, such as zinc plate and RS. plate (i.e., presensitized printing plate using diazotype light sensitive materials) have narrow light sensitive ranges and poor sensitivity and therefore printing with visible light, enlargement printing and reflection printing are difficult to be applied thereto, the advantage of the off-set printing plates provided by the present invention is extremely large due to their high sensitivity resulting from the utilization of a photographic silver halide emulsion.

(2) They may be used as matrices for dye transfer processes. Thus, a dye is adsorbed by gelatin partially existing on a support and then transferred, by any suitable means, to another suitable support.

(3) They may be used as screen printing plates by partially forming a gelatin film on an ink-permeable support, such as silk screen, thereby making the support ink-impermeable.

(4) When a water-hardly soluble or ditfusion resistant dye or pigment is previously incorporated into the gelatin layer, the resulting gelatin relief can be immediately visible and provided for further use, for example, as a transfer for the dye or pigment to another support using a suitable solvent for the dyes.

In the practice of the present invention, hardness of the gelatin layer or silver halide emulsion layer may be appropriately determined, depending upon specific purposes.

For example, in the case of using a gelatin-silver halide emulsion layer to form a gelatin relief therein, it is, of course, not desirable to strongly harden the emulsion layer. On the other hand, in the case Where a silver halide emulsion layer and an unhardened gelatin layer are brought into surface contact to form hardened images in the unhardened gelatin layer, it is advantageous to harden the silver halide emulsion layer by using a conventional diffusion resistant hardening agent. Furthermore, in the case where a material comprising a support successively provided thereon with a gelatin layer and a silver halide emulsion layer is employed, the gelatin layer should be an unhardened one and the emulsion layer should be a hardened one. In this case, when the upper emulsion layer is dissociated or stripped by treating with hot water after first developing, and fixing, there can be contemplated two modes of the dissociation, depending upon the bonding strength between the layers and upon the degree of progress of the hardening reaction; one mode where the unhardened areas of the lower gelatin layer are dissociated accompanying the upper layer and another mode where the hardened areas of the lower gelatin layer are dissociated accompanying the upper layer. The preferable conditions in such cases can be readily determined by a preliminary test.

A support carrying thereon the hardened gelatin images or gelatin relief images may be of, for example, glass, metal plate, cellulose acetate film, polyethylene telephthalate film, paper, synthetic paper, water proof paper or fabrics, such as silk screen. Suitable supports may be selected depending upon the specific purpose of its utili- Zation.

The present invention will be further explained in detail by the following examples, which are merely intended to be illustrative and not limitative of the present invention.

EXAMPLE 1 To g. of a conventional fine-grain positive silver chlorobromide emulsion (50' mol percent silver chloride) Was added 5 ml. of a 0.2 mol aqueous solution of Compound 1 and the mixture was applied to a glass plate followed by cooling to effect setting. After air-drying overnight at a temperature of 20 C., the sample thus formed was superposed on an original pattern and then exposed to effect contact exposure, whereafter it was developed at a temperature of 20 C. for 7 minutes and fixed for 20 minutes, using the following developing and fixing solution, respectively:

DEVELOPING SOLUTION G. N-rnethyl-p-aminophenol sulfate 2.0 Sodium sulfite 23.0 Hydroquinone 6.0 Sodium carbonate (monohydrate) 40.0 Potassium bromide 1.0 Water to make 1 liter.

FIXING SOLUTION G. Sodium thiosulfate 125.0 Sodium sulfite 9.0

Water to make 1 liter.

1 N aqueous NaOH solution to adjust the pH of the solution to a pH of 12.0

The sample was then dipped in warm water at 60 C. whereby the gelatin in the exposed areas where the gelatin-hardening reaction did not occur was softened and dissociated or dissolved away, while the gelatin remained on the glass plate in the unexposed areas Where the gelatinhardening occurred.

EXAMPLE 2 9 samples were prepared by adding several compounds of this invention, in amounts as shown in the table below, into 100 g. of a 3% aqueous gelatin solution and each sample was applied onto a triacetyl cellulose film, whereafter a composition was applied thereon, set by cooling and then dried, which composition was prepared by adding into a conventional optically sensitized high speed negative gelatin silver iodobromide emulsion (3.5 mol percent silver iodide, 3 g., per 100 g. said emulsion, of a high molecular weight hardening agent as disclosed in Example 1 of US. Pat. 3,362,827. The dry thickness of the gelatin layer and silver halide emulsion layer were 1.5 and 4a, respectively.

Amount of 0.1 mol aqueous Compound solution (ml.)

Each of these nine samples was subjected to enlargement exposure from a microfilm, whereafter it is developed and fixed with the same compositions as shown in Example 1. When the samples were dipped in hot water at 60 C. and the surface of such was rubbed therein, the upper silver halide emulsion layer was dissociated as a layer. Concurrently therewith, the hardened gelatin in the areas of the lower layer corresponding to the unexposed areas of the emulsion layer was also dissociated accompanying the upper silver halide emulsion layer. As the result thereof, there remained on the triacetyl cellulose base the unhardened gelatin corresponding to the exposed areas.

When these nine samples were processed with a printing ink for the off-set printing process, the ink Was deposited only on the areas where the gelatin was absent and the triacetyl cellulose base was exposed and transferred to a white paper to obtain duplicates.

Whereas, when these samples were each dipped in an aqueous solution containing tartrazine (CI 19140) to impregnate the gelatin areas with the dye followed by subjecting to dye transfer onto a white paper, there was obtained dye-transferred images of a yellow color.

As to the amount of the compound represented by Formula I, there is no critical limitation. The amount employed may vary widely depending on many factors and the preferable amount to be employed may be readily determined by those ordinarily skilled in the art of photographic procedures.

As to the heterocyclic ring represented by B in Formula I, there are noted thiazole, benzothiazole, naphthothiazole, thiazolone, thiazolenethione, thiadiazole, thiadiazoline, thiadiazolone, thiadiazolinethione, selenazole, benzoselenazole, naphthoselenazole, selenazoline, selenazolone, and selenazolinethione.

Although the present invention has been adequately described in the foregoing specification and examples included therein, it is readily apparent that various changes and modifications can be made without departing from the spirit and scope thereof.

What is claimed is:

1. A method for making hardened gelatin images, which comprises hardening gelatin in the non-silver image areas of a silver image-carrying gelatin silver halide emulsion in the presence of:

(a) a silver halide solvent,

(b) an alkali agent and (c) at least one compound of the Formula I:

wherein A and B are each non-metal atoms necessary for forming a heterocyclic ring, Y is a member selected from the group consisting of sulfur and selenium and X is an anion.

2. A method for making hardened gelatin images in a gelatin layer, which is in contact with a silver imagecarrying silver halide emulsion layer which comprises hardening gelatin in the gelatin layer in the areas corresponding to the non-silver image areas of the emulsion layer in the presence of:

(a) a silver halide solvent,

(b) an alkali agent and (c) at least one compound of the Formula I:

W opp i B Bruin @in S S S V S Ha C I' C1IL 4. The method of claim 2, wherein said compound is selected from the group consisting of and Br- Br- S S S S I t T N*' HaC-N N+ Br- Brand 5. A method for making a hardened gelatin image, which comprises treating a gelatin silver halide emulsion layer containing a silver image with a solution containing:

(a) a silver halide solvent,

(b) an alkali agent and (c) the compound of the Formula I of claim ll, thereby hardening the gelatin in the non-silver image areas.

6. A method for making hardened gelatin image, which comprises treating a gelatin silver halide emulsion layer containing a silver image with an aqueous alkaline fixing solution containing the compound of the Formula I of claim 1, thereby hardening the gelatin in the non-silver image areas.

7. A method for making a hardened gelatin image, which comprises treating a gelatin silver halide emulsion layer containing a silver image and the compound of the Formula I of claim 1 with a solution containing a silver halide solvent and an alkali agent.

8. The method of claim 2, wherein said silver halide emulsion layer is super coated on said gelatin layer.

9. The method of claim 8, wherein said silver halide emulsion layer contains the compound of Formula -I of claim 1.

10. The method of claim 8, wherein said gelatin layer contains the compound of Formula I of claim 1.

11. The method of claim 8, wherein said silver halide emulsion layer and said gelatin layer are treated with a solution containing the compound of Formula I of claim 1.

12. The method of claim 2, wherein said silver halide emulsion layer is superposed on said gelatin layer.

13. The method according to claim 12, wherein said silver halide emulsion layer contains the compounds of Formula I of claim 1.

14. The method of claim 12, wherein said gelatin layer contains the compound of Formula I of claim it.

15. The method of claim 12, wherein said superposed layers are treated with a solution containing the compound of Formula I of claim 1.

16. A method for forming a gelatin relief image, which comprises forming a hardened gelatin image according to claim 1 and removing any remaining unhardened gelatin to form the hardened relief image.

17. A method for forming a gelatin relief image, which comprises forming a hardened gelatin image according to claim 2 and removing any remaining unhardened gelatin to form the hardened relief image.

References Cited UNITED STATES PATENTS 3,490,911 1/1970 Burness et a1 96l 11 NORMAN G. TORCHIN, Primary Examiner R. L. SCHILLING, Assistant Examiner U.S. Cl. X.R. 9636 

